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  1. #1
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    2.4 GHz Antenna modding for longer range?

    Has anyone learned any way to mod their receiver's antenna or transmitter's output power to make their car have even longer reception range on the 2.4Ghz system? I know the full wavelength for this frequency is right under 5 inches so making a longer antenna might not help much. In the case of a 27mHz radio you have plenty room for improvement as far as antenna length since that full wave is something on the order of 35 feet. But aside from buying the TQI transmitter (which the range being better on this vs. my stock TQ radio is likely negligible) is their any way to increase the output from the antenna? I have 14500 4.2v li-ion cells which are basically AA sized batteries but higher voltage, lithium chemistry, of course I don't know the input voltage limits on the TQI transmitters.... Has anyone attempted to increase the radio's power output?
    Last edited by cajunlasers; 03-17-2013 at 10:45 PM.

  2. #2
    RC Turnbuckle Jr.
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    Make it any further then the 2.4 and you would need binoculars to see it. It has been tested to over 800ft!

  3. #3
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    I hear ya, I guess I can't ever leave well enough alone though. But 800 feet in ideal conditions I suppose. If I mounted a go cam on it I'd love for it to go 8000 ft then and I could control it from my couch to harass all the neighbors' loose running mutts - lol

    (of course THEN I'd need a long range wifi cam!!)

    The "problems" we face right?
    Last edited by cajunlasers; 03-17-2013 at 11:20 PM.

  4. #4
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    I've never fully tested mine. I have 20/20 vision but can't see my bright green Merv after about 350 ft.
    Drive. Crash. Fix. Repeat.

  5. #5
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    I have 20/10 vision and can see pretty far. Mostly I like overkill I think. If my car did 100mph I'd be fine with that even if I never drove it more than 50. Nice to know I have some to spare. With obstacles, trees, power lines and other interference around here including large radio and cell phone towers I need all the radio power I can get.
    Last edited by cajunlasers; 03-18-2013 at 04:33 PM.

  6. #6
    RC Turnbuckle Jr. Jimdog's Avatar
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    I don't think there is much you can do. I think it has more than enough range as it is.
    This will TOTALLY work, saw a guy on YouTube do it

  7. #7
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    Quote Originally Posted by 50togo View Post
    Make it any further then the 2.4 and you would need binoculars to see it. It has been tested to over 800ft!
    +1 on that, i drive mosly at night, and last time i lost eye contact with my merv, i search for it lik 15minutes before i did find it... 20feet down the river side!
    Summit RX8/1550kv-Slash4x4 MM2/2400kv Twin-V Merv.

  8. #8
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    Thanks everyone for your input on this topic

    Now lets see what else I can tinker with on it....

  9. #9
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    What i can say is this:

    On my losi mini 8, i puted 6,6v on the stock tx. It made more 20meters of range on the car! Don't know if the traxxas will allow 6,6v because of the AA*4=4.8v recahrgeables or AA*4=6V alkalines.... guess 0.6v does not hurt! On mine it did not hurt!
    but later i changed for the kyosho tx/rx because it got 100meters range.... which means 200meters range if you are in the middle! And that is enough for me, because i just can't see the car's that far....








    http://www.youtube.com/watch?v=hG1ig_qDEo0

    http://www.youtube.com/watch?v=fK9y7WPHEI0


    If you want the best range go for the sanwa mx11: http://www.youtube.com/watch?v=ryTCSoidJEc
    400meters, means 800meters, which is almost an 1km!

    More then that i only know helis or planes tx's! Which can go some km'h...

    Quote Originally Posted by cajunlasers View Post
    Thanks everyone for your input on this topic

    Now lets see what else I can tinker with on it....
    Last edited by targetingxmod; 03-19-2013 at 04:52 AM.

  10. #10
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    That's the idea I had in mind to try, step up the transmitter a bit on the voltage, since most electronics have a slight over and under voltage tolerance.
    The TQI transmitter requires 4 X AA batteries, 1.6V x 4 = 6.4V, I figured I'd make a Li-Ion pack of 4x14500's and wire in series parallel to get 8.4V. I have a variety of chargers for those, including a custom made USB charger.

  11. #11
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    Carefull, alkaline baterys are 1.5v, so 4*1.5=6v.

    I went with li-fe lipo because they got 3.3v each cell, so 3.3v*2=6.6v which is in the "safe" range. 8.4v will fry instant the electrics... i think!
    6.6v is lithium and is safer for that! Those li-fe i bough in a normal eletronic store!

    Lithium baterys are:
    3.3v is li-fe (lithium ferrite)
    3.6v is li-ion (lithium ion)
    3.7v is li-po (pilthium polimer)
    Quote Originally Posted by cajunlasers View Post
    That's the idea I had in mind to try, step up the transmitter a bit on the voltage, since most electronics have a slight over and under voltage tolerance.
    The TQI transmitter requires 4 X AA batteries, 1.6V x 4 = 6.4V, I figured I'd make a Li-Ion pack of 4x14500's and wire in series parallel to get 8.4V. I have a variety of chargers for those, including a custom made USB charger.

  12. #12
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    Quote Originally Posted by targetingxmod View Post
    Carefull, alkaline baterys are 1.5v, so 4*1.5=6v.

    I went with li-fe lipo because they got 3.3v each cell, so 3.3v*2=6.6v which is in the "safe" range. 8.4v will fry instant the electrics... i think!
    6.6v is lithium and is safer for that! Those li-fe i bough in a normal eletronic store!

    Lithium baterys are:
    3.3v is li-fe (lithium ferrite)
    3.6v is li-ion (lithium ion)
    3.7v is li-po (pilthium polimer)

    Yes you are right, 2 volts up might be too much just to try....

  13. #13
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    The transmitter itself operates on a different voltage than the rest of the transmitter system anyway, and 2.4ghz will only go so far due to FCC rules. You cannot modify it with a 2watt amplifier and expect it to be legal.

    There are other frequencies that propagate trees/hills/houses much better than 2.4ghz can.

    Wifi operates at 2.4ghz as well, so even IF you managed to boost your radio range, you would also need to boost your wifi camera range. That's where non wifi-band broadcasting comes in. I use 1.28ghz for video, it has the greatest quality vs range of all the frequencies I've found. 900mhz technically goes further but isn't as clean, where 5.8ghz is super clean, but as soon as you're behind a tree there's a bunch of static.

    So again, putting more power in to the battery tray of a transmitter won't do anything except burn out some other components, the 2.4ghz transmitter module itself operates at the same voltage regardless, until the batteries are drained so much it doesn't even receive the 5 volts it wants.

  14. #14
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    That's what I'm looking for, thanks krallopian!

    I'll have to look into the 1.28ghz video camera.

    Is 2 watts the limit on the 2.4ghz band?

    I assume WiFi has a pretty low power limit also, thus why we see very short range use on these devices that use it.

  15. #15
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    Wifi is 2.4ghz currently. Our transmitters are generally 100mw output as per the rules. Some people get boosters for their planes that are 500mw (not 5x the range, but much much better than stock) and now industrial places use 2-5watt boosters! Those get HOT, as in burn yourself hot.

    Your microwave is 2.4ghz, but usually around 1000watts (10,000x more powerful than your 4xAA transmitter) and that can cook your frozen meat in no time!

    So there's no LIMIT on the band technically, but the rules state: "You cannot modify your transmitter as it will no longer be within regulation." But they say the same thing about a real cars headlights, it is illegal to modify them - to put brighter ones, or different colour ones - but that doesn't stop people from doing it or selling/buying the equipment needed.

    I choose 1.28ghz because it provides the best range/clarity for where I am, but I know in America you are limited to what bands you can use, I'm not sure if 1280 is legal there or not. If it isn't, 1.2ghz will be. If you want to explore the FPV world more, google "Ground FPV" and you'll come across a wealth of information! Don't let those fancy mad-scientist looking antennas fool you either, they're only good for airplanes.

    *cheers

  16. #16
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    I used my new TQI transmitter for the first time today (had to shim my diffs and replace a suspension arm prior to) and on first use it would appear it has a longer range than the stock TQ transmitter, same exact batteries inside. Of course I haven't found out the true max range on it yet until I can bring the car to somewhere with more distance and no cars, etc. My old TQ seemed to work out to about 500-600 feet before it got out of solid controlling range by my best guess, going by the property length I'm living on at the moment. My next range test, I will use my wheel measuring tool. This TQI never got out of range and I was able to go at least 50-75 feet further before I reached a pond. There is something I have learned, the TQI with the telemetry base option has the ability to add a rechargeable battery pack - a 5 cell NiMH #3037 and charger #6545. The charger was not able to be found after a brief search, does anyone know if the 6 amp ez-peak plus will work with that battery? Even with an adapter?

    EDIT: It will, there is an adapter included with the EZ Peak plus that plugs into the pack directly, just not the charger base. So the pack has to come out to charge that's all.

    The upgrade there, aside from *recharge-ability* is the 8 volts from 5 x 1.6v cells vs. 6.4v from 4 x 1.6v cells alkaline. Which answers the other question from the beginning - the transmitter can handle at least 8v input safely. Whether this increases range or not - I'll find out later. Not to argue with anyone here... 800 feet sounds like a lot but when you're covering around 70+ feet per second it's not that much if you straight line it out of range. I have excellent eyesight, the more range the better.
    If we were flying RC planes, if you only had 800 feet you'd be crashing all day long I would think.
    Last edited by cajunlasers; 03-25-2013 at 02:57 PM.

  17. #17
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    You could use a fractal pattern on the receiver antenna, maybe boosting the range.

  18. #18
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    Quote Originally Posted by ian-slash View Post
    You could use a fractal pattern on the receiver antenna, maybe boosting the range.
    Would that make it more of a directional antenna?

    I found that the TQI telemetry receiver has a shorter antenna wire than the stock TQ receiver, it won't even come close to sticking out the antenna tube. Can't understand why the difference in length when it operates on the same frequency.
    @ 2.4 GHz (even) the full wavelength is 4.92 inches, so perhaps an antenna wire double or even triple this length would enhance the range somewhat, of course then, who wants a 15 inch long antenna on their mini?

    The NiMH pack I just ordered may make a difference, I'll post my findings after I test both 4 x AA and 5 cell NiMH pack.

  19. #19
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    You won't want to change the length because its optimized to be the best at that length, right? So maybe the fractal pattern isn't the best idea. Also, fractal pattern wouldn't make it directional, it just amplifies the signal....with math... Lol

  20. #20
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    Quote Originally Posted by ian-slash View Post
    You won't want to change the length because its optimized to be the best at that length, right? So maybe the fractal pattern isn't the best idea. Also, fractal pattern wouldn't make it directional, it just amplifies the signal....with math... Lol
    If you double the antenna length - would the added height not add some range?

    Just curious what would such an antenna look like for 2.4GHz?

    I GPS'd mine today at 475 feet before I ran out of room, which is farther than it looks (in grass). I'm just nit picking at things with the distance, only due to my interest later in adding a wireless camera, I know anything beyond 500 feet for a car is awesome in a normal circumstance.

  21. #21
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    Length of the wire is not going to change distance much at all. The only part that actually receives the signal is the ~3cm that sticks out past the metal part. All the rest between that and the receiver is just for routing.
    Whatever it is I just typed... could be wrong.

  22. #22
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    He's suggesting changing the size of the ~3cm portion, as that represents the waveform. The ~3cm length is a 1/4 wavelength of the 2.4ghz band, and a 12.5cm is a full wavelength. So if you want a half, or quarter, or even an eighth they would all work with varying degrees of effectiveness. I'm not sure what happens if you make a 25cm length one though (double wavelength) so I can't answer there... the black magic known as RF is all too mysterious for me.

  23. #23
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    Quote Originally Posted by Jimmie Neutron View Post
    Length of the wire is not going to change distance much at all. The only part that actually receives the signal is the ~3cm that sticks out past the metal part. All the rest between that and the receiver is just for routing.
    I figured the added height would help a little, being that the cars can hide behind tall grass, etc. I agree the internal wiring won't account for much receiving.

    Back in my CB Radio days, the longer antennas worked much better than the shorter ones, of course, understandably 27MHz is a far longer wavelength. But also to be noted when my "base station" (if you will) antenna was raised up higher on a tall pole and properly grounded, ground planes, etc. SWR set up good, the extra height noticeably increased the reception range. Granted this is all on a larger scale of things, the concept is the same.

  24. #24
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    Quote Originally Posted by krallopian View Post
    He's suggesting changing the size of the ~3cm portion, as that represents the waveform. The ~3cm length is a 1/4 wavelength of the 2.4ghz band, and a 12.5cm is a full wavelength. So if you want a half, or quarter, or even an eighth they would all work with varying degrees of effectiveness. I'm not sure what happens if you make a 25cm length one though (double wavelength) so I can't answer there... the black magic known as RF is all too mysterious for me.
    If I remember back from electronics school, the promulgation of radio waves tends to work in a way that the receiving antenna should be oriented in the same manner as the transmitting one, if one it pointing up the other needs to be also for the best possible capture of the waves. (Making those curvy antenna tubes useless for reception in my book). A full wave of 2.4GHz is right under 5 inches, so your best case scenario would be the portion exposed to capturing the radio waved needs to be that length, and that portion high enough to receive the waves. I used to cut to length according to a chart depending on the given frequency for different two way radios I've owned over the years. These were little magnet mount car antennas - and you cut the antenna wire to the exact length for the frequency, if you cut it too short or a little too long it wouldn't work as good. The only thing left to do after setting proper antenna length and getting it as high as possible is amplification. I'll take height over amplification though.

    For CB radios the SWR (standing wave ratio) was measured to get the best possible signal reciprocity. This is undoubtedly something traxxas does at the factory when designing their radio systems. And even with the best set ups, interference is sometimes unavoidable with so many radio waves in the air now a days.

  25. #25
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    Quote Originally Posted by cajunlasers View Post

    Is 2 watts the limit on the 2.4ghz band?
    Currently studying for my HAM license; FCC regulates telecommand signals to 1 watt max.

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